1. Field of the Invention
The present invention relates generally to a connector adapter for installing a connector that is attached to the end of a cable onto a terminal post and more particularly to a means for assuring a proper torque setting of an electrical cable connector, wherein the cable is a coaxial cable or the like, installed in functional systems.
2. Description of the Prior Art
In the past, connectors and more particularly, electrical connectors have been installed by turning the connector “by-hand” without the use of tools. This by-hand procedure is convenient and fast, however the “finger tight” connector-to-terminal post engagement does not provide the necessary torque required for a variety of applications. For example, in space flight applications, a required torque level is necessary for accelerometer cable connectors to avoid the occurrence of loosening due to various vibrations that transpire during certain flight phases such as ascent, on-orbit operations, and descent. As another example, in terrestrial-based applications, a required torque level is necessary in certain electrical connectors to avoid moisture penetration to protect high impedance contacts. As still another example, in certain electrical connectors, a required torque level is necessary to compress elastic fillers in a terminal post and secure a pin or a plurality of sockets connected to wires extending from the connector to their functional terminals. Accurate torque application is necessary to preclude under or over compression of the connector filler with consequences of loss of electrical contact at its pins or sockets, or distortion of the same through over tightening. Thus, a manufacturer for a particular connector may require a specific torque range for proper operation of their connectors.
Open-end wrenches have been and are employed directly to the connector to obtain a tighter connection. However, post access with this bulky tool is difficult, and the connection is sometimes over-tightened resulting in damage to the connector, post, or both. Further, off-center wrench applicators often provide erroneous readings and result in slippage of contact surfaces. To address these problems, a variety of adapter devices have been developed in connection with a proper applicator tool. These devices all vary in design and purpose. Most devices are limited to operating on hexagonal-head connectors, because hexagonal-head connectors are generally the industry standard. Therefore, these devices do not address the issue of operating on non-hexagonal head connectors, such as, for example, round connectors. Further, as will be discussed in more detail infra, most devices have a means for establishing a pre-application hoop compression load to hold the connector in place before installing the connector. There are two primary designs in the prior art for establishing this pre-application hoop compression load.
The first primary type of design is described in U.S. Pat. No. 4,945,791, issued on Aug. 7, 1990, to Herschler et al., who discloses an adapter used for applying a specified torque to the back shells of electrical connectors. Herschler et al. uses a clamping means with a separable closure and adjustable friction-producing strap bonded to the outer lower lip of the adapter for establishing a pre-application hoop compression load. A user inserts the connector in Herschler's adapter and then proceeds to tighten the clamping means with a separate tool so that the friction-producing strap firmly compresses the connector against the inner surface of the adapter. For obvious reasons, use of Herschler's invention, although functional, is time-consuming and awkward.
The second primary type of design is described in U.S. Pat. No. 5,415,065, issued on May 16, 1995, to McMills, who discloses a hand tool employed to tighten a connector nut at the end of an electrical cable on a cable terminal post. McMills uses sleeve, which is separable from the body member of his hand tool. A user inserts the connector in McMills' hand tool and then slides the separate sleeve over the end of the hand tool wherein the connector now resides. McMills' hand tool is tapered such that when the user slides the sleeve the compression load is increased as the sleeve is slid further along the hand tool. McMills' design is also functional, but the use of a separate sleeve member can result in the user losing or misplacing the separate sleeve member. Further the user may inadequately slide the sleeve, which can result in the sleeve falling off before the user installs the connector. In addition, the hand tool's working load tension has a critical value above which the tensile expansion of the sleeve permits the side walls of the hand tool to slip around the connector when a predetermined torque value is exceeded. Thus, the sleeve is directly dependent to meeting the proper torque value.
It would be desirable to design a more elegant approach for installing a connector attached to a cable to address the variety of problems that still exist in the prior art.